It’s a good idea to periodically test whether your garage door opener’s safety system works as designed.
Just because the garage door opener moves the door up and down doesn’t mean it’s moving it safely and correctly. Here are a few simple tests to make sure your opener is working the way it should.
Check that the garage door moves freely
While your garage door is closed, disconnect the door from the opener drive mechanism by pulling the emergency release cord until it unhooks the connection latch.
Open and close the door; it should move smoothly and easily on the rollers in the tracks. If the door doesn’t glide freely, contact a professional for repairs.
Test the garage door opener’s auto-reverse
If the door passes the first test, reconnect the door to the opener drive mechanism and use the garage door opener to open the door completely.
To test the auto-reverse feature, lay a full roll of paper towels in its side on the ground, centered under the garage door. Use the garage door opener to close the door.
The door should come down onto the roll of towels, compress the roll and then automatically reverse direction. If the door doesn’t reverse direction when it compresses the roll or reverses before it compresses the roll, adjust the sensitivity control. You can find instructions in the owner’s manual for the garage door opener.
Test the sensors
To test the safety sensors, open the garage door and locate one of the sensors at the bottom of a door rail. Have a broom or something similar within reach.
Push the control button to close the garage door. Before the door closes fully, place the broom in front of one of the sensors to interrupt the invisible beam of infrared light from the sensor. Blocking the beam should cause the door to stop and reverse immediately. If the door doesn’t reverse, check the alignment of the sensors. If that doesn't fix the problem, some of the repairs in this video can help,